The qualifying "Invasion" rounds are over, the Underdog roster is official and — by this time next week — The Challenge will have evolved into a duel between a collective David and Goliath. But are this game’s misfits ready for the uphill battle ahead?

On tonight’s episode, The Underdogs learned that only four more spots — two for women and two for men — were available in The Oasis: Two would be earned at the subsequent mission, and the remaining two would be decided by an ensuing elimination round. Some of those left in suspension, like Nelson and LaToya, were motivated by the prospect of getting closer and exploring romance together, while Amanda was determined to score the ultimate prize to help her ailing father. Then there was Anthony, who was desperate to chip away at his student loan debt.

No matter their incentive, each contestant fought tooth and nail through "Caged and Confused," a mini-Houdini act that defied the Underdogs to roll individual cages across a field before setting themselves free. LaToya got the early lead on the women’s side with a seemingly decisive sprint, but Amanda’s slow-and-steady method ultimately prevailed and made her the champion. On the men's side, it was a buzzer beater between Shane and Anthony, but the former — who got his Challenge start 15 years ago — earned his ticket.

"It feels amazing to know I’m getting out of The Shelter," Amanda said. "No more muddy nights, no more fleas flicking around, no more bugs, no more poop talk."

Then, with only one last chance left at securing a spot in The Oasis, Sylvia, LaToya, Anthony and Nelson began feeling the heat. In “Thai Rise,” a timed event, each competitor had to race up — and then back down — a skyscraping series of stairs that soared 1,000 feet high and changed shape, width and steepness throughout. And, as if that weren’t difficult enough, the competitors were met with torrential rainfall, slippery surfaces and, in LaToya’s case, a rather aggressive wild monkey who was reluctant to let her pass.

The race was tight on both sides, but when all four competitors finally made it back from the race’s summit, it was Nelson and Sylvia who’d won The Oasis’ last spots. For Sylvia, The Shelter’s presumed loser, the win was especially gratifying.

"I'm so excited I started crying," she said. "I think I've proven to everyone back at The Shelter that I am a competitor and I'm here to compete."

And the excitement spilled over into Nelson's and Sylvia's return to The Shelter, when they learned the remaining Underdogs were finally moving from squalor to luxury. And The Oasis didn't disappoint — there were huge rooms, a catalog-worthy pool and showers that didn’t rest on dirt floors. Still, the party couldn’t last, and when day broke over Thailand, the Underdogs were met with a shock they never saw coming — the arrival of The Champions.

"To be a champion, you’ve gotta beat The Champions," TJ said as competitors like Johnny Bananas, CT and Laurel manifested out of nowhere.

"There’s no need to pinch yourself -- your worst nightmare has just come true," Bananas said. And by the look on some of the Underdogs’ faces, his assessment didn’t seem too far off.

What do you think — will this group of Underdogs be able to keep the Champions at bay, and can they finally pull out big wins? Or would some of the eliminated Underdogs have been stronger assets than those who made the cut? Share your thoughts, and see what happens when these two teams collide next Tuesday at 9/8c!